Deposition of thin films using non-vacuum techniques normally comprises either sol gel or metal organic materials or comprises photochemical metal organic depositions. Films of inorganic materials are usually deposited by chemical or physical vapor deposition, although in some cases, sol gel or metal organic deposition has been used. The sol gel or metal organic depositions require the construction of films of precursors. These films are then heated to drive off the organic component, leaving a metal or more commonly, a metal oxide film. The photochemical deposition method differs from the above two methods in that the reaction which drives off the organic component is photochemically activated. Since none of these methods are able to form the patterned structures normally used in the construction of microelectronic devices or circuits, they must be employed with other processes in order to pattern films of materials.
Hybrid methods often use light as the energy source wherein the light used initiates a thermal rather than a photochemical reaction. These methods have the disadvantage that they do not directly result in the formation of patterned films but result in the unselective deposition of the films.
Additional disadvantages of the previously described deposition methods are that they require the use of expensive equipment and many of them require high temperature processing.
Because of the problems associated with possible contamination of clean room facilities, a single chemical which may be used for different deposition methods is desirable. Furthermore, the use of a single chemical for different deposition methods reduces the product development expense to the supplier.
Metals, such as copper, may be used as a conductor in electronic circuits. Other metal oxides, such as copper oxide, are semiconductors and have found use as a conductor in electronic circuitry. Accordingly there is much interest in developing methods of achieving the deposition of metals and the patterned deposition of metals or their oxides on various substrates.
U.S. Pat. No. 5,534,312 to Hill et al., incorporated herein by reference, describes a method for the deposition of a variety of metal and metal oxide systems using photochemical deposition. It will be appreciated that the approach discussed therein is a substantial improvement in the prior art. The current invention presents new types of metal complexes or precursors which are useful for thermal, electron beam, and photochemical patterning of copper containing materials and a method for depositing these complexes.
Prior art precursors used to deposit metal or metal oxide films, such as that shown below, and disclosed in U.S. Pat. No. 5,534,312, are known to fragment under photolytic conditions, leading to the loss of CO2. This fragmentation leaves the metal atoms unbound. 
Complexes disclosed by Chung et al. in J. Chem. Soc., Dalton Trans., 1997, p. 2825-29, which is incorporated herein by reference, also comprise a pair of metal atoms bonded to bidentate organic ligands. The most general form of these complexes has the following formula. In the above formula, the individual sites where substitution may be used to optimize the physical and chemical properties are shown. The organic ligand framework of these complexes shows no obvious site for fragmentation under, for example, photolytic conditions. Therefore, it is not clear that complexes of this formula should be suitable for photolytic deposition of metals or metal oxides. In fact it could reasonably be predicted that the photochemical reactivity should center about the groups X1 and X2 in the figure. Indeed, the published photochemistry for this complex (Chung et al., (1997) J. Chem. Soc. Dalton Trans., 2825) leads one of skill in the art to expect that photochemistry should yield a stable Cu(I) complex. In an amorphous film comprising such a complex, however, Cu metal is formed. These precursors of the form shown above have been found to be useful in depositing films composed of a metal, such as copper, or its oxides.
Dielectric layers play an important role in the production and protection of individual semiconductor elements in integrated circuits (IC). SiO2 is one of the most important materials used for these proposes. See, for a description of important properties of this dielectric, Balk, Peter, (Ed.) Material Science Monograph, 32. The Si—SiO2 System. Elsevier. Amsterdam, The Netherlands, 1988. SiO2 finds extensive applications as an insulator due to its excellent dielectric constant (between about 3.1 to 4.1 for fused silica, according to G. V. Samsonov (Ed.), The Oxide Handbook. Second Ed. IFI/Plenum. New York, Washington, London, 204, 1992) and the good electronic properties of the Si/SiO2 interface.
In an integrated circuit, the production of a high quality Si/SiO2 interface is crucial to the performance of many electronics devices. For this reason deposition methods which cause minimal substrate damage, are of interest and attracted great attention. As low temperature deposition methods, Sol-Gel is one widely preferred method. However, in this depositional processes the quality of the Si and of the Si/SiO2 interface has not been of sufficient quality to be useful with integrated circuits without further processing.
Thin films can be easily deposited by the Sol-Gel method using techniques such as dip, spin and spray coating. The first two methods have been used successfully in obtaining thin film layers of optical quality. See Sol-Gel Science and Technology, 8, 1083,1997, for process details. One of the most attractive features of the sol-gel method is that thin films can be prepared without expensive equipment and high temperature processes. Surfaces ranging from a few mm to many meters in size can be coated (by dip coating). In spite of much effort, the sol-gel derived films have micrometer size pores and organic impurities in their structures, and thus actually require heat treatments above 400° C. to obtain a dense homogeneous structure, as described by Oh, Junrok; Imai, Hiroaki; and Hirashima, Hiroshi; J. Non-crystalline Solid, 241, 91, 1998.
Heat treatment are extremely important when depositing high quality SiO2 thin films for optical applications. Generally after heating at 500° C. for one hour, thin films are still porous, but after a heat treatment at 1000° C. for 5-min a complete densification of the thin film is observed. Densification can occur by the rearrangement of the strained SiO2 network through the cleavage of Si—O bonds by water molecules. This process can be represented by the following sequence of reactions: 
Therefore, this heating process can produce homogeneous and denser structures, according to Oh et al. It has been reported by Imai, H.; Moritomo, H.; Tominaga, A.; and Hirashima, H. J. Sol-Gel Sci. Technology, 10, 45, 1997, that in studies of the densification of silica gel films with exposure to water vapor that the water molecule acts as a catalyst. The sol gel method needs technological development, especially in thickness control, a very important issue for optical coatings.
Other methods to prepare thin films of SiO2 have been developed. These include sputtering and chemical vapor deposition (CVD), as described in Jpn. J. Appl. Phys, 36,1922, 1997. These methods have the disadvantage of the substrate reaching temperatures high enough to induce surface diffusion. These methods also require high vacuum conditions, which makes the deposition expensive.
Atmospheric pressure CVD has attracted attention because it produces good quality SiO2 films at low deposition temperatures (350-400° C.), as described by Jpn. J. Appl. Phys, 36,1922, 1997. The films were deposited from (SiH4+O2) mixtures in N2 carrier gas. Martin, J. G.; O'Neal, H. E., Ring, M. A.; Roberts, D. A.; and Hochberg, A. K., in J. Electrochem. Soc. 142, 3873, 1995 described approaches that have used tetraethoxysilane (TEOS) as starting material. TEOS has gained wide interest because it forms films of superior quality with high dielectric breakdown strength. Moreover, the conformal coverage is better than the one produced with SiH4, as described by Wrobel, A. M.; Walkiewicz-Pretrzykowska, A.; Wickramanayaka, S.; and Hatanaka, Y., in J. Electrochem. Soc. 145, 2866, 1998.
New methods of selective deposition of SiO2 on silicon make use of hydrogen passivated silicon surfaces. Local oxidation is introduced by using STM, AFM, or electron beam lithography. Of course, these methods are not suitable for large area patterning due to the long writing times.
Photolithography with photoresists is another method of depositing patterned layers of silica. Of course, this involves numerous additional steps of depositing and removing photoresists.
What is needed is a process for the deposition of a SiO2 thin film of sufficient dielectric properties at room temperature in a short number of steps. What is also needed is a method of forming layers of patterned metal and dielectric material with a minimum of process steps. What is also needed is a process of forming an amorphous dielectric material of a specific predetermined thickness. What is also needed is a method of incorporating additives to alter the dielectric constant, or the catalytic activity, or other property of the dielectric material in a short number of steps, wherein the process may be performed advantageously at near ambient temperature.